February 3, 2021 3:16 PM, "Graham Cobb" <g.bt...@cobb.uk.net> wrote:
> On 03/02/2021 21:54, jos...@mailmag.net wrote: > >> Good Evening. >> >> I have a large BTRFS array, (14 Drives, ~100 TB RAW) which has been having >> problems mounting on >> boot without timing out. This causes the system to drop to emergency mode. I >> am then able to mount >> the array in emergency mode and all data appears fine, but upon reboot it >> fails again. >> >> I actually first had this problem around a year ago, and initially put >> considerable effort into >> extending the timeout in systemd, as I believed that to be the problem. >> However, all the methods I >> attempted did not work properly or caused the system to continue booting >> before the array was >> mounted, causing all sorts of issues. Eventually, I was able to almost >> completely resolve it by >> defragmenting the extent tree and subvolume tree for each subvolume. (btrfs >> fi defrag >> /mountpoint/subvolume/) This seemed to reduce the time required to mount, >> and made it mount on boot >> the majority of the time. > > Not what you asked, but adding "x-systemd.mount-timeout=180s" to the > mount options in /etc/fstab works reliably for me to extend the timeout. > Of course, my largest filesystem is only 20TB, across only two devices > (two lvm-over-LUKS, each on separate physical drives) but it has very > heavy use of snapshot creation and deletion. I also run with commit=15 > as power is not too reliable here and losing power is the most frequent > cause of a reboot. Thanks for the suggestion, but I have not been able to get this method to work either. Here's what my fstab looks like, let me know if this is not what you meant! UUID={snip} / ext4 errors=remount-ro 0 0 UUID={snip} /mnt/data btrfs defaults,noatime,compress-force=zstd:2,x-systemd.mount-timeout=300s 0 0 However, the system still fails to mount in less than 5 minutes, and drops to emergency mode. Upon checking dmesg logs, it is clear the system is only wait 120 seconds, before giving up on mounting, and dropping to emergency mode. --Joshua